Construction of ecological network in Qujing city based on MSPA and MCR models.

With the rapid advancement of urbanization and industrialization, ecological patches within cities and towns are fragmented and ecological corridors are cut off, regional ecological security is threatened and sustainable development is hindered. Building an ecological network that conforms to regional realities can connect fragmented patches, protect biodiversity and regional characteristics, and provide scientific reference for regional ecological protection and ecological network planning. By taking Qilin District, the main urban area of Qujing City as an example, and using geospatial data as the main data source, based on morphological spatial pattern analysis (MSPA) and minimum cumulative resistance (MCR), this study identified ecological source areas, extracted ecological corridors, and build & optimize ecological networks. (1) All landscape types are identified based on MSPA, the proportion of core area was the highest among all landscape types, which was 80.69%, combined with the connectivity evaluation, 14 important ecological source areas were selected. (2) 91 potential ecological corridors were extracted through MCR and gravity models, there were 16 important ones. (3) The network connectivity analysis method is used to calculate the α, ß, and γ indexes of the ecological network before optimization, which were 2.36, 6.5, and 2.53, while after optimization, α, ß and γ indices were 3.8, 9.5 and 3.5, respectively. The combined application of MSPA-MCR model and ecological network connectivity analysis evaluation is conducive to improving the structure and functionality of ecological network.

Study on the influence of urban tree canopy on thermal environment in Luoping County.

Urban forest is an integral part of the complex urban ecosystem, and tree canopy plays a key role in improving urban climatic environment. Urban Tree Canopy (UTC) is strongly linked to urban thermal environment and living quality of residents. In this study, Luoping County, a mountainous county in southwest China, was selected as the study area to uncover the inner connections between tree canopy and thermal environment, and provide relevant scientific references for the construction of livable forest cities in similar areas. Through eCongnition Developer, ENVI and ArcGIS software, the distribution of Land Surface Temperature (LST) and land cover types in the study area was extracted, 63 patches with super-large and extra-large tree canopy coverage selected, to explore the regulatory effect of UTC patches on urban thermal environment based on SPSS software. Results showed that the highest LST in the research area was 37.63 â„ƒ, the lowest 24.73 â„ƒ, and the average 30.83 â„ƒ. Among the land cover types, the area of buildings and impervious surfaces was 1615.71 hm2, accounting for 55.76% of the total study area, which was the largest proportion and with widespread distribution; the area of grassland and water body was 57.48 hm2 and 12.35 hm2, respectively, taking up 1.98% and 0.43%, with a smaller proportion. Mean LST: impervious surface > bare land > grassland > tree canopy > water body. By increasing the area and perimeter of the patch covered by tree canopy, the cooling rate of the patch can be increased while the temperature inside the patch can be reduced. The relationship between the area and cooling rate is closer than that between perimeter and cooling rate. The increase of perimeter has a stronger alleviation effect on the internal temperature of the patch, whereas, the increase of area has a weaker effect in this respect.

Removal of atrazine from submerged soil using vetiver grass (Chrysopogon zizanioides L.).

The long-term widespread application of atrazine poses significant threats to the eco-environment and human health. To investigate the potential of vetiver (Chrysopogon zizanioides L.) for phytoremediation of the environmental media contaminated by atrazine, an indoor incubation experiment was conducted in submerged soil over 30 days. Results showed that the chlorophyll level of the vetiver was not significantly affected by exposure to atrazine. Vetiver could take up and accumulate atrazine from submerged soil and peaked around the 20th day with a concentration of 1.0 mg kg-1 in leaf. The metabolites Hydroxyatrazine (HA), deethylatrazine (DEA), Deisopropylatrazine (DIA), and didealkylatrazine (DDA) were detected in the leaf on the 30th day, indicating vetiver could degrade atrazine inside the leaf tissue. The atrazine removal rate in the vetiver planted and unplanted jars were 69.72 and 60.29%, respectively, indicating that 9.43% higher atrazine removal was achieved in the presence of vetiver (p < 0.05). The atrazine dissipation in the submerged soil followed first-order kinetics, the degradation constant was 0.066, and the half-life of atrazine dissipation was shortened by 6.86 days in the presence of vetiver. The present study suggests that vetiver can take up atrazine from submerged soil and accumulate in the leaf, which could then degrade in the leaf.Novelty statement: Although the fate of atrazine in agricultural soils has been extensively investigated through various experiments, little is known about the effect of vetiver grass on atrazine dissipation from submerged soil. With the identification of soil-leaf transportation and four metabolites in vetiver leaf and soils, significantly accelerated atrazine dissipation from the submerged soil was achieved in the presence of vetiver. Particularly, the formation of less toxic dealkylated products in the leaf indicated vetiver is a promising grass for atrazine removal from submerged soil.

The study of transcriptome sequencing for flower coloration in different anthesis stages of alpine ornamental herb (Meconopsis 'Lingholm').

Meconopsis (Papaveraceae) is an interesting alpine herb, mainly distributed in the mountainous area of southwest China and high altitude zone in Tibetan-Himalaya. Different Meconopsis species showed a flower color alteration in different anthesis stages, Meconopsis 'Lingholm' is one of the localized species whose petal color changes from purple to blue during the flowering process. In general, the blue color flower is a rare kind, and usually hard to cultivate artificially. The molecular mechanism of flower color formation and color alteration of alpine flowers were reported by many research workers. To find critical genes that regulate Meconopsis 'Lingholm' color alteration and the mechanism of environmental adaptation, the current study performed transcriptome sequencing by using Meconopsis 'Lingholm' petals from different anthesis stages. There were totally 91,615 unigenes obtained from 31.4 Gb sequencing data, and differentially expressed genes between two consecutive flowering stages were obtained. Bioinformatics studies showed genes regulating petal color alteration were activated. Moreover, the functional analysis showed that Meconopsis 'Lingholm' showed a stress response to mechanical damage, non-biological stimulation and water deficiency in the bud stage, as well as showed a stress response to the cold from cracking stage to blooming stage. Furthermore, RNA-Seq results were verified using nine randomly selected genes by qPCR, which showed same expression trend with sequencing results. During this study, 20 candidate genes identified for further studies, which included five petal color related genes and 15 environmental response genes.